A federal appeals court has ruled that an Arizona utility company can be held liable for violations of antitrust laws after it charged its customers higher rates for electricity if they chose to install solar panels on their rooftops. The 9th Circuit Court of Appeals found evidence that the Salt River Project utility company structured its pricing to unlawfully thwart competition from solar energy systems. Some Salt River Project customers in Phoenix saw their electricity prices rise by more than 60% after they installed solar panels on their homes.